Containers of this type can be used as beaker-shaped or box-shaped packagings for milk, butter, margarine and similar commodities. Such containers may be of different height and shape and can, for example, be round, rectangular or oval. In certain applications, containers of extremely flat design also occur such as plates or bowls for pre-cooked meals. In these versions the container has an extremely wide opening which is closed by means of a large flat lid. There is an extremely strong need to be able to ensure that a container of the above-mentioned type, once it has been filled and sealed, cannot be unauthorizedly opened fully or partially without it being noticed by the end user of the contents of the packaging. Particularly in connection with thin-wall thermoplastic containers, difficulty is experienced with presently-known techniques in ensuring this as in such designs it is not possible to arrange a secure form of sealing.
The problems have been solved as regards containers for disposable use since on such containers the opening is covered by a foil lid of plastic, for example, or by a plastic-metal compound foil which is positioned and sealed to the edge of the opening. When opening such a filled originally-closed container the lid foil is torn off, which precludes re-use of the lid for closing the container.